New RFI in Yaesu FT-450 (

Dave, KD0DK, has operated mainly with his Yaesu FT450D and it worked flawlessly, until recently it has been shutting down when he uses 20 meters. This has happened while transmtting between 75-100 watts. What's going on?
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[@timbacchus]

Would love to hear what he finds as the problem. This is one reason that radio is so much fun

[@andrewhill4226]

Check that the power supply you use is set at 13.8volts if you have a variable voltage dial. We had issues on Field Day with a power supply that was slightly off the 13.8volt setting and the radio would not do 100 watts and cut out a few times. Cheers Andy M6APJ

[@Homer19521]

I second Andrews comments below. Check the voltage at the radio's connector, while the radio is set for 100W (RTTY or CW) into a dummy load.

[@lbwl]

Found the model MFJ-915 on DX Engineering site that looks similar to the one you were holding.

[@lyfandeth]

Ferrites from no-name sources aren't always reliable. I go to Palomar or DX Engineering or another prime vendor if I want chokes that are guaranteed right.

[@kenenglish124]

Hardly any ads on Amazon for ferrites mention the "mix" of the material. The mixture of the two or three metals (with the epoxy powder) determines the frequency range that will be absorbed.
Most of the ones on Amazon are just surplus from the computer industry, and do not work below 25 MHz.
That's why there are so many negative reviews.... they got the wrong version.

[@angelhelp6819]

Good afternoon Dave I like all your videos they're very excellent I give you a hundred percent on I have the yesu 450 d is a very good unit

[@Porco_Utah]

may be a voltage drop during TX. most radio today shut itself down when input voltage get below threshold around 11V or so. AG6JU

[@rogerlafrance6355]

I suspect swr. At 100watts CW, the full dissipation of the pa is in use and besides swr it could trip the current and thermal overloads. A dummy load is an important thing to test your rig at high power.

[@mikebavoso26]

Hello, I had this same extact same problem while operating moble. I was pluging the rig in the cigarette lighter. When I was using the 450D in my travel tralier and had the same problem. The answer is low voltage at the 450D.

[@clems6989]

I suspect the DC voltage is dropping. And maybe not RFI.
The power supply may be heating up and dropping voltage at 100W.
Measure the dc voltage at 100W output.
He didn't say if radio goes "off" and stays off ? Or does output just drop out ?
Also, RF in the shack will show up many places, most notably in the speaker or audio of nearby equipment. (PC speakers etc).
Good luck. Never except that you have to tolerate this. Amateur radio is all about figuring out these things...

[@johanburwicknyberg7975]

How about accumulated dust inside impairing the cooling?

[@chr2810gt]

I'm having the same issue - whenever I transmit on 20m, I get RFI. No issues on any other bands but only on 20m

[@walterslover1056]

I have a FT 450D that works fine. New Choke Cookbook is a great source for reference a PDF is down loadable. On my coax I use 10 turns on 240 by 43 mix torrid as a common mode choke. On my DC power from the power supply, I wrapped 12 turns clockwise. And on the other side of the 240 by 43 mix torrid, I wrapped 12 turns counterclockwise. One coil positive and the other negative. Also watch OG's Grounding Videos 73s KC0ELC

[@jamessawyer4625]

roger on the MFJ web site it was the best a few months or a year ago. not now.

[@cliffyoung5712]

Dave. My FT450D doesnt shut down from RFI. More likely its a heat issue from dust or pet hair.

[@g0fvt]

I think you have likely hit the nail on the head with this one. There are a number of other possibilities mentioned in the comments but I think common mode current derived RFI is highly likely. 73

[@James_Bowie]

MFJ-915, RF ISOLATOR, 1.8-30MHz, 1500W PEP
I often wonder what MFJ would be like if its owner actually gave a hoot about managing it properly.

[@goodnewsfromgod-bybob5710]

MFJ is hard to search.

[@DominicMazoch]

MFJ website is not George Jetson friendly.

[@clems6989]

MFJ has a perfect product line. But the engineering and quality control is crap. I think its a shame because like I said, they have a great product lineup...

[@tomnorman5461]

Fix your collar Dave...last three videos.